Association between shoulder pain, muscle strength, and closed kinetic chain performance tests in swimming athletes: Cross-sectional study

Context This cross-sectional study examined whether shoulder pain and muscle strength of kinetic chain components are associated with performance on the modified Closed Kinetic Chain Upper Extremity Stability Test (mCKCUEST), Upper Quarter Y Balance Test (UQYBT), and Upper Limb Rotation Test (ULRT) in swimmers. Methods Sixty-two competitive swimmers (aged 12–60 years; 30 with shoulder pain, 32 asymptomatic) across all competition levels were included. Isometric strength of the scapular protractors, lower trapezius, trunk flexors, Hip Stability Isometric Test (HIPSIT), and knee extensor was assessed. Participants also completed the mCKCUEST, UQYBT, and ULRT. Hierarchical multiple linear regression analyses were conducted to examine the associations between shoulder pain, kinetic chain muscle strength, and upper limb performance tests. Results The model explained 28% of the variance in mCKCUEST performance, with shoulder pain and HIPSIT reaching statistical significance. Knee extensors and scapular protractors strength were significantly associated with the medial direction of the UQYBT, explaining 35% of the variance. Lower trapezius strength was associated with the superolateral direction (11% of variance), while knee extensor strength was associated with the inferolateral direction (37% of variance). Knee extensors and scapular protractors strength were associated with the composite score (38% of variance). For the ULRT, pain, scapular protractors, knee extensors, and trunk flexors strength showed significant associations, explaining 38% of the variance. Discussion Shoulder pain and isometric strength of kinetic chain muscles may be associated with performance on the mCKCUEST, UQYBT, and ULRT, highlighting the relevance of kinetic chain assessment in swimmers.